Laser induced phenomena on semiconductor devices are used for example for failure analysis techniques for a variety of semiconductor devices. Examples of such failure analysis techniques include light induced voltage alteration (LIVA) techniques, thermally induced voltage alteration (TIVA) techniques, optical beam induced current (OBIC) techniques, and optical beam induced resistance change (OBIRCH) techniques.
Existing systems for implementing the above mentioned techniques have each been applied to failure analysis for particular purposes and conditions. However, existing systems do have certain limitations and disadvantages, which have hindered any one system from being suitable for a wide variety of analysis purposes and conditions.
For example, existing systems for TIVA and LIVA techniques use constant current biasing and an AC coupled amplifier. For an active device under test (DUT), due to voltage fluctuations such devices typically require a current surge during power-up, before reaching a stand-by state. The current surge can be several orders of magnitudes higher than the stand-by biasing current, and typical occurs over a very short period, for example in the order of μsec. Therefore, both TIVA and LIVA techniques, using constant current biasing, cannot provide the required current surge for proper power-up of an active DUT, and therefore existing TIVA and LIVA systems are typically limited to being applied to passive DUTs. In addition, using a constant current bias may lead to increase in DUT voltage during laser irradiation which may lead to DUT damage due to voltage over-stress.
As another example, existing OBIRCH systems, which are based on measuring changes in a current flow through the DUT, have been found to provide a lower sensitivity of the technique compared to TIVA and LIVA systems, for example. Furthermore, in OBIRCH systems, switching resistors in the measurement circuit to adjust sensitivity can effect a change of the DUT state as it changes the current that is being applied to the DUT.
As another example, a voltage bias and voltage change detection system uses an active reactive component in the measurement circuit. The use of the active reactive component may result in a back voltage which may cause damage to the measurement instrument or the DUT.
A need therefore exists for an alternative monitoring and measurement method and system for laser induced phenomena applications on semiconductor devices, which may address one or more of the above mentioned limitations and disadvantages.